ABSTRACT
During recent years, attention was drawn to the role of cell adhesion in tumour development and progression. Cell-cell and cell-extracellular matrix interaction is crucial with regard to tumorous transformation and tumour spreading. There are numerous data indicating that the expression of syndecan-1 an important transmembrane proteoglycan undergoes changes during the development of several tumours. CD 138 antibody reacts with the core protein of syndecan-1, cell surface integral membrane heparin sulfate and chondroitin sulfate containing proteoglycan that binds to interstitial extracellular matrix molecules, thereby regulating cell adhesion. The predominant location of syndecan-1 is on epithelial cells where its expression correlates with normal epithelial organization. Previous studies have demonstrated that decreased expression of CD 138 is linked to malignant progression. Hitherto, few studies on the expression of CD138 in odontogenic tumours have been published and no studies have been found regarding the expression of this marker in adenomatoid odontogenic tumour [AOT]. Therefore, this study was carried out to highlight the recent concepts of cell adhesion in tumour development and progression in AOT using CD 138 monoclonal antibody. In respect to this, formalin-fixed, paraffinembedded tissue sections of 7 cases of AOT were selected in an attempt to clarify the peculiar histopathological features of this lesion. All studied cases showed positive reaction to the marker used, however differences were observed among the studied cases regarding areas of immunoreactivity and optical density of the positive areas. Overexpressions of CD138 were observed as cytoplasmic immunoreactivity especially in the spindle cells bordering the sheets and masses of the polyhedral cells and in the scanty stromal cells. The duct like structures and masses of polyhedral cells showed negative reactions. The results of the present study explain why AOT is a benign non-aggressive lesion